Hydrachna goldfeldi Thor, 1916

Davids, Kees, Sabatino, Antonio Di, Gerecke, Reinhard, Gledhill, Terence & Smit, Harry, 2005, On the taxonomy of water mites (Acari: Hydrachnidia) described from the Palaearctic, part 1: Hydrachnidae, Limnocharidae and Eylaidae, Zootaxa 1061, pp. 36-64 : 44

Hydrachna goldfeldi Thor, 1916

Material examined: Lectotype female, here designated, SMNH 5971 Ucraina, Kiew, Goldfeld leg., ex coll. Thor; Russia, Yaroslavl, Nekouz, temporary reservoir near village Pogorelka, VI 1994 coll. Tuzovskij. The specimens curated at Stockholm survive as a gift from Thor to Lundblad prior to the destruction of the former authors collection. Thor did not designate a holotype, the collector was killed in 1917, and no further remnants of his collection are preserved elsewhere. This is the last remnant of the syntypes and designated here as lectotype in order to provide taxonomic stability.

Discussion: Important measurements of the lectotype are as follows: Coxal field L 1250; frontal sclerite L/W 820/2900, genital field L/W 330/520; gnathosomal base L 470, rostrum L 550; chelicera L 1240, palp total L 1030, segments L/H P­1 200/340 (0.59), P­2 290/195 (1.49), P­3 350/100 (3.50), P­4 140/65 (2.15), P­5 L/H 50/28 (1.79); P­2 with six dorsal and one lateral, P­3 with two dorsal and two lateral setae; P­1 with one dorsodistal seta. Measurements for females from the original description (in parentheses those of the specimen from the collection of Tuzovskij): Idiosoma L/W 3000–4500/2600–4000; frontal sclerite L 880; coxal field L 1120, W 2550, W max Cx­3 550, Cx­4 incl. projection 960, genital field (measurements erroneously reversed by Thor, here corrected) L/W 300–360/ 600 (400/560); "rostrum" (probably erroneous term referring to the entire gnathosoma) L 1000 (gnathosoma L 1000, rostrum L 500); chelicera L 1300; palp measurements (obviously, Thor gives the total, not dorsal L for P­1) L/H P­1 325/330 (180/330), P­2 250/ 175 (250/170), P­3 350/? (320/85), P­4 138 /? (135/55), P­5 50/? (50/25).